This invention relates to boat anchors and more particularly to highly efficient anchors having a low weight to holding power ratio.
Anchors typically include a plow portion having laterally extending flukes, which are coupled to an elongated shank that is fixed to the plow portion or hinged thereto. The free end of the shank is connected, in use, to a chain and then generally to a rope that connects to the boat. The anchor must be useful both for anchoring in sandy, muddy, clay and gravel bottoms as well as against a rocky bottom or a bottom covered with grass or other undergrowth. Hinged shanks present problems of corrosion and poor operation at the hinge as well as a potential hazard to the mariner who handles and works with the anchor. An anchor of the hinged type is offered by Simpson Lawrence USA, Inc., Bradentown, Fla., U.S.A., and a one-piece anchor is provided by Bruce International Limited, Onchan, Isle of Man, Great Britain. The anchor by Bruce has a shank that includes substantially a right angle bend. Both of these products are generally well accepted in boating circles.
In all of the prior art anchors, the chain attaches at the shank end most remote from the plow flukes. Thus, the entire length of the shank must be sufficiently thick to withstand stresses that tend to bend the shank when the anchor is being dragged into its initial holding position. Even with a heavy shank construction, when anchoring on a rocky bottom, the plow flukes may catch on a rock and cause bending around the rock of the elongated shank. A further difficulty with the long shank is that when anchoring in sand or mud, a considerable drag distance is required before the plow flukes penetrate deeply enough into the bottom to restrain the boat. Weight of the anchor for a given size and holding power is also a very important convenience factor in using and handling an anchor and in maintaining it on the boat when not in use.
Accordingly, it is desirable that the greatest holding power be provided with an anchor having low weight and a compact non-deforming structure. A long shank works against these objectives in that extra strength is necessary to resist bending, especially when anchoring on a rocky bottom, as discussed above.
What is needed is a boat anchor that has a low weight to holding power ratio, is of small size, simple construction and suited for use on all types of sea bottoms, whether sandy, rocky or overgrown with underwater foliage.